The invention relates to a bumper assembly for a passenger car and to a passenger car having such a bumper assembly.
Such bumper assemblies for passenger cars are known sufficiently from the series production of vehicles. The bumper assembly comprises a bumper cover by means of which a flexible cross member extending in the transverse direction of the vehicle is covered. For this purpose, the bumper cover is arranged in front of the flexible cross member in the longitudinal direction of the vehicle, wherein the flexible cross member is covered to the front by the bumper cover in the longitudinal direction of the vehicle.
The bumper assembly also comprises at least one reinforcement element for reinforcing the bumper cover at least underneath the flexible cross member. For this purpose, the reinforcement element is arranged underneath the flexible cross member at least partially in the longitudinal direction of the vehicle.
The reinforcement element is usually also referred to as a “lower stiffener”, as a “lower bumper stiffener” or else also as a “lower load path”. The reinforcement element serves to reinforce the bumper cover, in particular in the case of force application owing to an accident. If, for example, the lower leg of a pedestrian, which can be simulated by a leg impacter, impacts against the bumper cover, the reinforcement element (“lower stiffener”) which is arranged underneath the flexible cross member ensures that the pedestrian is accelerated with a corresponding force in the region of his lower legs and therefore is moved in a defined fashion onto a front hood. Such a “lower stiffener” can be found to be disclosed in, for example, US 2011/0127798 A1.
Furthermore, it is known from the series production of vehicles to use sensors to sense collisions of the passenger car with pedestrians. Such a sensor can reliably detect collisions with pedestrians and supply necessary information to safety devices of the passenger car in order to trigger, as a result of the collision, protection measures for protecting the pedestrian. For this purpose, it may be provided, for example, that within 10 to 15 ms after the collision the front hood, which is embodied, for example, as an active engine hood, is correspondingly actuated and raised by actuators. In this context, the front hood is moved upward in the vertical direction of the vehicle and, for example, forward in the longitudinal direction of the vehicle in order to increase the distance between the front hood and an engine block which is arranged underneath it in the vertical direction of the vehicle. As a result, valuable protection space can be provided at least to reduce the consequences of the accident.
Usually, in order to sense such a collision with a pedestrian, a hose which extends in the transverse direction of the vehicle is used, by means of which hose the flexible cross member is covered to the front at least in certain areas in the longitudinal direction of the vehicle. Owing to a collision of the passenger car with a pedestrian, the hose is deformed, which results in turn in a change in pressure in the hose. This change in pressure can be sensed by means of at least one sensor, with the result that the collision with the pedestrian can ultimately be sensed.
Such collision sensing devices are known, for example, from DE 10 2008 021 611 A1 and DE 10 2010 000 223 A1.
The use of the hose leads, however, to a large number of parts and therefore to a high weight and to a large installation space requirement in the passenger car, in particular in the front region thereof.
The present invention therefore has, as one object, making available a bumper assembly of the type mentioned at the beginning and a passenger car having such a bumper assembly, by means of both of which a collision of the passenger car with a pedestrian can be sensed in a manner which is, in particular, favorable in terms of weight and installation space.
This object is achieved by a bumper assembly having the features of the independent claims. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the other claims.
Such a bumper assembly for a passenger car comprises a bumper cover for covering a flexible cross member and at least one reinforcement element for reinforcing the bumper cover at least underneath the flexible cross member. As described in the introduction, such a reinforcement element is usually also referred to as a “lower stiffener”, as a “lower bumper stiffener” or else also as a “lower load path”.
In order then to be able to sense any collision of the passenger car with a pedestrian in a way which is, in particular, favorable in terms of installation space and weight, at least one sensor, which is coupled to the reinforcement element, is provided for sensing a deformation of the reinforcement element which results from a collision of the car with a pedestrian. This means that the reinforcement element which is present in any case is used to sense a collision of the passenger car with a pedestrian. An additional component, for example a hose, is therefore not provided, and not necessary, for sensing a collision of the passenger car with a pedestrian.
In the bumper assembly according to the invention, the reinforcement element and its function described at the beginning, to accelerate the pedestrian in the region of his lower legs and as a result to convey said pedestrian in a defined fashion onto a front hood of the passenger car, are used in order also to sense the collision itself. The invention is based here on the idea that in the case of a collision of the passenger car, and in particular of the bumper assembly, with the pedestrian, an application of force owing to the accident and a resulting deformation of the reinforcement element occur in any case, and this can then be used by means of the at least one sensor to sense the collision.
The reinforcement element is therefore assigned a double function. On the one hand, it serves to convey the pedestrian onto the front hood in a targeted fashion, with the result that said passenger does not move under the passenger car but instead can roll in a targeted fashion on the front hood and can therefore be protected. On the other hand, the reinforcement element is used to sense the collision itself owing to the application of force to the reinforcement element resulting from the collision with the pedestrian.
Owing to the sensing of the collision, at least one protective measure can be initiated to protect the pedestrian further in the further course of the collision. In the scope of this at least one protective measure, for example at least one actuator element of the front hood is actuated in order to move the front hood up, i.e. to extend it, at least in the vertical direction of the vehicle by means of the actuator element. As described at the beginning, it is therefore possible to enlarge a distance from the front hood to a drive assembly of the passenger car which is arranged underneath the front hood in the vertical direction of the vehicle, in order thereby to provide additional protection space for the pedestrian.
In one particularly advantageous refinement of the invention, the reinforcement element has at least one chamber filled with a gas, in particular air, which chamber can be deformed as a result of the collision with the pedestrian, and to which the at least one sensor is coupled. In this case, the sensor is configured to sense a change in pressure in the chamber resulting from the deformation of the chamber. In other words, a change in pressure in the chamber results from the deformation thereof, wherein this change in pressure can be sensed by means of the sensor. In this way, the collision with the pedestrian can be inferred in a particularly simple way which is favorable in terms of weight and with only a very small number of parts.
It proves particularly advantageous if the at least one sensor is coupled to the chamber at a first end thereof, wherein at least one second sensor, by means of which a change in pressure in the chamber resulting from the deformation of the chamber can be sensed, is coupled to the chamber at a second end thereof, spaced apart from the first end in the transverse direction of the vehicle. As a result of the use of the at least two sensors which are spaced apart from one another in the transverse direction of the vehicle, not only the collision with the pedestrian per se can be sensed. In addition it is possible also to sense a location or a region of the reinforcement element, and therefore of the bumper assembly, at which or in which the collision with the pedestrian has taken place. Therefore, a position of an impact region in which the pedestrian impacts against the bumper assembly can be determined relative to the bumper assembly as a whole or with respect to the passenger car, with the result that the at least one protective measure can be carried out as a function of the determined position.
As a result it is possible, for example, to adapt the process of extending the front hood to the position of the impact region. The front hood can therefore, for example, be moved into different positions by means of at least one actuator element depending on the position determined for the impact region. As a result, particularly good protection of the pedestrian can be made available.
In a particularly advantageous embodiment of the invention, the reinforcement element, in particular the chamber, extends over an at least major part of the width of the passenger car extending in the transverse direction of the vehicle. As a result, such a collision of the passenger car with a pedestrian can also be sensed in a way which is favorable in terms of weight, cost and installation space, such a collision taking place in the edge regions or corner regions of the passenger car. As a result, the pedestrian can be particularly effectively protected.
In a further advantageous refinement of the invention, the reinforcement element is supported on a carrier element, in particular a longitudinal carrier, of the passenger car. As a result, the bumper cover can be reinforced particularly well by means of the reinforcement element, since the reinforcement element itself is supported on the carrier element in a particularly stable and fixed fashion. As a result, the pedestrian can be accelerated very well in the region of his lower legs and advantageously conveyed onto the front hood. Furthermore, this support benefits the sensing of the collision since a deformation of the reinforcement element and resulting sensing of the collision can occur particularly early during the collision.
In order to implement support of the reinforcement element in a way which is particularly fixed and favorable in terms of installation space, there is provision that the flexible cross member is also supported on the carrier element, in particular the longitudinal carrier. As a result, the expenditure for supporting the reinforcement element can be kept particularly low.
Particularly advantageous reinforcement of the bumper cover can be implemented if the reinforcement element is secured to the carrier element independently of the bumper cover. This means that, for example, the bumper cover can be removed, that is to say detached from the passenger car, without as a result the attachment of the reinforcement element to the carrier element being adversely affected, and vice versa. In other words, the bumper cover can be removed without the reinforcement element having to be removed as well.
In this context there is preferably provision that the reinforcement element is not attached to the bumper cover.
In a further embodiment, the reinforcement element is embodied in an inherently rigid fashion, that is to say is dimensionally stable. The reinforcement element is preferably not elastically deformable here such as, for example, a foam. In addition, there is preferably provision that the reinforcement element is formed from a material which is different from a foam.
A further embodiment is defined by the fact that the reinforcement element is, in particular, completely spaced apart from the bumper cover in the longitudinal direction of the vehicle. The reinforcement element is preferably, in particular, completely, spaced apart from the bumper cover rearward in the longitudinal direction of the vehicle. The term “completely spaced apart” is to be understood as meaning that the reinforcement element is not in contact with the bumper cover in an undeformed state, that is to say not at any point.
In addition it is possible to provide that the reinforcement element is embodied as a component which is embodied separately from the bumper cover. In other words, the bumper cover and the reinforcement element are, for example, two separate components which can be secured, that is to say mounted, separately, that is to say independently of one another, on the passenger car. This means that the reinforcement element and the bumper cover are each independently secured to the passenger car without the bumper cover being necessary to secure the reinforcement element to the passenger car or the reinforcement element being necessary to secure the bumper cover to the passenger car.
The invention also includes a passenger car having a bumper assembly according to the invention. Advantageous refinements of the bumper assembly according to the invention are to be considered as advantageous refinements of the passenger car according to the invention, and vice versa. Owing to the use of the reinforcement element both to accelerate the pedestrian in the region of his lower legs and to sense the collision itself, a particularly advantageous accident behavior of the passenger car can be implemented in a way which is favorable in terms of cost, weight and installation space, since additional sensors such as, for example, a pressure hose are not provided and are not necessary for sensing the pedestrian collision.
Further advantages, features and details of the invention can be found in the following description of a preferred exemplary embodiment and with reference to the drawing. The features and combinations of features which are specified in the description above and the features and combinations of features which are specified below in the description of the figures and/or those which are only shown in the figures can be used not only in the respective specified combination but also in other combinations or alone without departing from the scope of the invention.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.